Control Global

Beamex has announced it will be providing the racing team with calibration equipment for the season's final race at Silverstone.

Beamex has announced it will be teaming up with young racing driver Mark Draghicescu and his Speedsport racing team for the final race of the season at Silverstone, providing calibration equipment to hopefully meet the demanding needs of automotive and auto sport technologies. As everyone gears up for the final race of the season, Mark's Speesport racing team and Beamex hope this partnership can lead to Mark reaching the highest level of the sport, and Beamex providing equipment to assure the performance gain is consistent.

Many U.S. wastewater treatment plants (WWTPs) are beginning to use anaerobic digesters to produce biogas that can be used in their combined heat and power plants to generate electricity and heat. In addition, the plants are selling the biogas into the gas grid. The growing interest in biogas has led to more attention paid to measuring biogas flow and composition, because proper gas engine operationsdepends upon use of biogas with the right methane (CH4) content. New ultrasonic technology, including the OPTISONIC 7300, developed by Krohne, Inc., is being developed to provide the kind of reliable and accurate flow measurement needed to advance this important strategic energy source.
United States looks to biogas for fossil fuel alternatives…

Differential pressure transmitters are reliable, cost effective instruments to measure the hydrostatic level of a liquid in a vented or sealed tank.

Differential pressure sensors are cost effective and reliable instruments that measure the hydrostatic level of a liquid in a vented or sealed tank, and it's important to understand exactly how to utilize them to their full potential.
For a vented tank, the pressure transmitter should be mounted to the bottom. Typically, the transmitter will be threaded into the outlet line of the tank, a side bung or flange. Since a pressure transmitter provides a linear output signal, such as a 4 to 20mA signal from zero pressure to the full scale pressure, the level can be monitored based on the liquid density and the height of the tank.
For Example: Density of water at 4°C = 1 Height of tank = 35 feet = 420 inches 27.68…

Measuring pressure or calibrating pressure instruments is not that easy. These online resources can help.

Pressure In Hazardous Areas
In controlled environments, pressure measurement is relatively straightforward. However, in the mobile equipment industry and other hazardous areas, application variables can have a huge impact on pressure measurement accuracy. The consequences for pressure measurement errors can be widespread and potentially dangerous. Fortunately, by anticipating and accommodating challenges in pressure measurement common in hazardous environments, operators and engineers can prevent misreadings, damage to equipment or personnel injury, and costly downtime. This whitepaper addresses several common and sometimes difficult application challenges that need to be considered when selecting a pressure sensor, as well as some…

The International Society of Automation and Beamex will be co-hosting a free, web seminar September 1, 2015 on how to calibrate temperature instruments.

On September 1, 2015, the International Society of Automation (ISA) and Beamex will be co-hosting a a free web seminar on calibrating temperature instruments.
From 12 p.m. to 1:30 p.m. EST, the webinar will feature three temperature instrumentation experts: Tom Brans, Business Analyst at Honeywell; Ned Espy, Technical Director at Beamex; and Roy Tomalino, Professional Services Engineer at Beamex.
Temperature influences many physical features of matter and has a significant impact on quality, energy consumption and environmental emissions. It's no surprise then that temperature tends to be the most common and frequently measurable variable in the process industry. However, many people don't know the proper ways to calibrate temperature…

BLH Nobel Introduced a System That Quickly and Easily Checks Weighing Systems for Wiring and Mechanical Faults

Load cell weighing systems solve some of the knottiest problems in batch and level control by directly measuring masses of solids and liquids as they're accumulated, dispensed or conveyed. But the load cells must be installed and wired properly, and the load structure must be engineered and constructed correctly to distribute the measured load as axial forces on the cells. What appear on the surface to be simple wiring and construction tasks have caused more than a few problems during commissioning and maintenance due to miswired or poorly made connections, distorted or binding structures, incorrectly installed load cells or rigid connections to adjacent equipment.
Such problems often are not found until a new installation is being…

Greg McMillan and Stan Weiner Speak with Electrochemical Measurements Expert Jim Gray About the pH Electrode and Its Full Potential as a Measuring Tool

Stan: A measurement is only as good as its calibration. The pH electrode has by far the greatest sensitivity and rangeability of any measurement in the process industry. The electrode can function well in a wide spectrum of process fluids and…

This month, the editors of Control browse the web to get you the latest online resources on loop control. Here's how you can stay in the loop!

This System Is Closed
This is a basic tutorial on closed-loop control systems. It covers the basic definitions and descriptions of how closed-loop systems work, a discussion of closed-loop summing points and how to use them, transfer functions, multi-loop closed-loop systems and closed-loop motor control. The direct link is www.electronics-tutorials.ws/systems/closed-loop-system.html.Electronics Tutorials www.electronics-tutorials.ws
PID Control
VeriCal in-situ calibration verification This is a basic discussion, with illustrations, of the principles of Proportional, Integral, Derivative (PID) and how it is used with controllers. It also covers tuning rules and starting settingf for common control loops. The direct link is at…

Is it too hard, too complicated, too expensive, or does it just have a bad rap? Maybe all it needs is better marketing.

Stan: I have gotten the distinct impression from a number of users that the term "Advanced Control" is viewed negatively. I was wondering in general who feels this way (e.g., plant management, process design, operators) and why (e.g., support,…

Father of the PLC Dick Morley sets the record straight on PC-based control and what differentiates it from PLCs.

Dick Morley is considered by many to be the father of the programmable logic controller (PLC). His involvement with the creation of the first Modicon PLC for General Motors in 1968 was a historic step in the development of industrial controls.
We had the chance to sit down with Morley and ask him a variety of questions. In this third installment of our series, Morley explains the difference between the PLC and PC-based control.
Watch the previous two installments here:
The father of the PLC talks about the Internet of Things
The father of the PLC explains its birth

Advanced Control Systems receives certification from the laboratory of testing equipment and materials (LAPEM).

Advanced Control Systems (ACS) recently announced at the annual RVP-AI/2015 IEEE Mexico Conference that the laboratory of testing equipment and materials (LAPEM), an organization of the Comisión Federal de Electricidad (CFE), has awarded the company the distinguished certification from the institution that meets the needs of the electricity sector nationally and internationally.
The LAPEM certification process is a lengthy one, filled with registrations and extensive audits of ACS processes, service management, technical support and system technology.
"We are very pleased to receive such an honor," said ACS CEO Kevin Sullivan, "from such a reputable institution in our industry. LAPEM is greatly respected in providing specialized…

Control Engineering Branches Out to Manage Critical Business Variables Such as Profitability, Risk, Asset Management and Cybersecurity

Most process engineers I talk to look back on the 1970s and 1980s as the heyday of control engineering, and in many ways it was. More engineers were focused on the applications of real-time control theory then than now. And when you look at how far…

NEXCOM's new IPPC 1560TE is ingition-proof, explosion-proof and ready for anything.

NEXCOM has unveiled its new IPPC 1560TE panel PC, perfect for the hazardous locations few PCs are able to go. It has been certified by UL for class 1 division 2 (C1D2) hazardous location (HazLoc). This ensures the PC is explosion and ignition-proof, reaffirming its safety in environments including oil and gas, petrochemical manufacturing, steel and chemical industries.
UL listed, ATEX or IECEx certifications are a must in locations where flammable gases, vapors or liquids might exist. As one fire or explosion can be incredibly costly in terms of lives and money, its important to have the necessary precautions in place before tragedy strikes your facility.
In addition to the assurances against fires and explosions, the IPPC 1560TE also…

Flying with a robot at the controls could be a tough sell; How many level gauges do you need for an accurate measurement?

Q: Pilots or robots in the cockpit?
You have written many times about the potentials of automation in improving air transportation safety and efficiency. Besides writing your columns, have you done anything about that? Is ISA, NASA or anybody else…

According to the U.S. Department of Energy, misapplications of control valves in pumping systems offer a significant opportunity to save energy.(5) This article explains how the pump and control valve should be selected to save pumping energy and…

A reader asks our experts how he can prove that the actuator is large enough to handle actual process conditions. Our experts answer.

Re the February 2015 Control Talk column on the commissioning of control valves (How to Avoid Problems in Electrical and Instrument Installations): How does one go about proving that the actuator is sized large enough to handle actual process…

The editors of Control search the world wide web to find the latest online resources on motors and drives.

GROWN-UP MOTOR DRIVES
Motors and drives have been moving up to variable-speed control for better accuracy, but now they're also increasing power density and efficiency, and even coordinating more closely with PLCs and intelligent systems, according to Control executive editor Jim Montague. Learn how process operations as diverse a cement suppliers, iron ore mines, refineries and natural gas producers are using the latest drive technology in increase efficiency, reduce power usage and improve reliability. Read "Motors and Drives Grow Up and Graduate."Controlwww.controlglobal.com
A THREE-STEP PROGRAM
This three-minute video from ABB explains the basics of motor and drive sizing. Learn the three steps around application requirements, sizing…

Solutions for every stage of the process sensing, instrumentation, analysis, interface, networking and control experience light up exhibition space at Honeywell User Group America 2015.

Some user group meetings have so much good content that it starts to slosh over the sides of that metaphorical bucket. That's definitely the case at Honeywell User Group Americas 2015, where a brief Sunday afternoon preview of the demo room featured…

Rockwell Automation introduces its new Allen Bradley MobileView tethered operator interface. The mobile terminal gives plant and industrial personnel the freedom to take a machine’s human-machine interface (HMI) with them to make real-time adjustments to out-of-view applications.The inclusion of a hardwired e-stop button and three-position enabling switch also supports applications that require local safety functionality.
“Between making an adjustment on the terminal and viewing the results on the machine, fixed operator terminals can require a lot of back and forth for personnel, for certain applications,” said Matt Hansen, senior product manager atRockwell Automation. “The MobileView tethered operator interface puts the…

Operators responding to abnormal situations need better designed systems. The challenge is not inundating the operator while being sure to wake them up.

Consultants focusing on operator effectiveness have been known to draw some inspiration from military aircraft designs, which incorporate a lot of graphical depictions of flight and combat variables on their cockpit "heads-up" displays. The present…

The GX and GP Products Are the First of a New SmartDAC+ Product Family

Yokogawa has released the GX and GP Series of digital data acquisition systems, products that go far beyond functionality of the original paperless recorder. Complementing Yokogawa's DXA Advanced R4 series, the GX and GP bring some features that are…

Studies show that poorly performing alarm systems and poorly designed human machine interfaces (HMIs) are contributing factors to major accidents and poor operating performance. Speaking this week at the Schneider Electric 2015 Global Automation…

Process safety metrics based on leading indicators can help head off incident and injury

Industry puts substantial effort into ensuring that plants are designed and built to run safely. By their very nature, however, the safety instrumented systems (SIS) that often carry a lion's share of the plant's risk reduction measures are seldom…

The FieldComm Group is dedicated to advancing intelligent integration in process control and instrumentation, and its official introduction to the global process industry is planned for the 2015 ACHEMA Fair in Frankfurt, Germany, June 15-19.

The FieldComm Group was founded in January 2015 with the combining of two leading automation industry consortiums — the Fieldbus Foundation and HART Communication Foundation. The new organization is dedicated to advancing intelligent integration in process control and instrumentation, and its official introduction to the global process industry is planned for the 2015 ACHEMA Fair in Frankfurt, Germany, June 15-19.
With 170,000 attendees from more than 100 countries and 3,800 exhibitors, ACHEMA is the most comprehensive event for process manufacturing. By creating a larger-than-life "Technology Wall" in Hall 11.0, Booth E43, the FieldComm Group will show attendees how it is "connecting the world of process automation’" through solutions…

ISA100 Wireless is an open, flexible, scalable and IoT-enabled framework for process industry applications. The underlying technology is based on IEC 62734 and has been widely deployed around the world. This webinar will present an up-to-date introduction to ISA100 Wireless architecture as it is typically implemented and used today. The three main topics that will be included are the following:
-The major applications addressed by ISA100 Wireless.
-Network architectures, from point solutions to IIoT.
-Overview of the IEC 62734 standard.
The webinar will be presented by Jay Werb, Technical Director of the ISA100 Wireless Compliance Institute. Users evaluating industrial wireless technologies, suppliers building industrial wireless…

The next COTS technology waiting to take hold in process automation is lithium-ion batteries.

Remember when the PC was introduced back in the early 1980s? Most thought it would never be reliable enough for any type of process automation application. Fast forward 35 years, and it's impossible to find a DCS without PCs at the server level,…

Solutions for every stage of the process sensing, instrumentation, analysis, interface, networking and control experience light up exhibition space at Honeywell User Group America 2015.

Some user group meetings have so much good content that it starts to slosh over the sides of that metaphorical bucket. That's definitely the case at Honeywell User Group Americas 2015, where a brief Sunday afternoon preview of the demo room featured…

"Mobility is a philosophy about enabling users and improving productivity," said Kyle Reissner, Integrated Architecture mobility platform leader, Rockwell Automation. "Here at TechED, we're focusing on how mobility is being incorporated across all…

Prior to selecting an ac line reactor or a dc link reactor for mitigating the impact of harmonics in variable frequency drive (VFD) applications, it is prudent to carefully review the advantages and shortcomings of both and select the one that is better for that particular application.
Our sister publication Control Design, published the article "When to use an ac or dc choke and why" to help visitors determine the pros and cons of ac line and dc link reactors.
Check the table below to see the pros an cons and read the full article to learn more.

The huge Indian textile, refining and soon-to-be telecom provider streamlines from 500 legacy systems at 120 plants to just 35 standardized applications—and transforms its workplace environment at the same time.

Everyone knows to keep it simple, but it's rare that any simplification project is as gigantic as Reliance Industries Ltd.'s recent effort to update and standardize many of the legacy process automation and other systems at six major sites…

New tools are available to help mine the vast quantities of useful plant information that have accumulated over the years

It takes a lot of drawings and documents to run a process plant. Unfortunately, much of this information is stored in different and seemingly incompatible ways, such as on paper, in photographs, in proprietary CAD and other databases, and in legacy…

Fueled by the transferable ANSI/ISA-88 standard and streamlined by software, batch control is reaching escape velocity in its traditional processes, and migrating to new worlds of applications.

Julius Caesar usually gets the credit for "divide and conquer," but there's evidence he was just the most famous in a long line of ancient rulers to use it. That's the way with any great idea—everybody wants to make it work for them. Of course,…

In March, Dyneon GmbH opened and began operating the world’s first pilot plant to recycle end-of-life fluoropolymer materials in Burgkirchen, Germany. Dyneon selected a HIMatrix safety controller from safety specialist HIMA as the emergency shutdown (ESD) system in order to safeguard the plant's depolymerization reactor. The safety system transitions the plant to a safe status in the event of excess temperatures being reached to exclude the possibility of risks for people and the environment.
The compact, modular HIMatrix safety controller was developed especially for applications that require from just a few I/Os to several hundred I/Os. Its efficiency, compactness and simple assembly of the various control and remote I/O modules…

With increasingly connected systems, SIS is becoming prone to more cyber risks and vulnerabilities.

The SIS market is growing, and growing fast. By 2020, it is expected to be worth $3.76 billion in the U.S. alone. However, with this increased connectivity, the numerous cyber risks associated with these systems are coming with them. To prevent severe incidents at plants that could impact human life, assets and production, the challenges linked to these systems must be met with substantial protection.
According to new research, increasing Industrial Internet of Things (IIoT) and Big Data adoption within industrial settings is anticipated to lead to substantial growth in the number of interconnected industrial control devices during the next five years.
The once-isolated SIS now faces multiple potential cyber threat paths. As a result,…

Part of building expected to fall completely as firefighters scramble for a plan.

Panic struck Peterborough, Ontario, Canada last month when the Genpak plant's roof collapse and emergency services staff were forced to evacuate.
The gas feed to the building was shut off and firefighters evacuated everyone from the building, but shingles continued to fall and the roof continued to dip slowly. Firefighters were scrambling to develop a plan in case the roof collapsed completely.
Witnesses say new shingles were loaded on the roof yesterday, in preparation for repairs.The City's chief building official went into the plant shortly after 10 a.m. to take a look at the structure.
Located at 25 Aylmer St. North, Genpak has 61 employees. It specializes in process packaging for a wide range of products.

Intertec is seeing increased customer demand for equipment housings to contain wireless process monitoring equipment in outdoor environments. The company attributes this partly to increased use of industrial wireless sensor network (WSN) technology, but mainly to the growing industry awareness that the glass-reinforced polymer (GRP) composite material it uses for all of its protective enclosures is electromagnetically transparent.
Until recently, process industry take-up of WSN technology has been relatively slow, possibly because competing wireless standards have made systems designers wary of making the wrong choice. However, for mainstream industrial process applications, the field has now narrowed to just two standards –…

New trends and old friends in network choices

Industrial process automation: Wireless and Ethernet technologies are taking over today's trendy solutions, but dont count out the classics like the fieldbuses, which remain old favorites that still are in high demand.

HOW DO YOU take yours? Straight up with a twist or with syrup and berries? As we've reported frequently in this magazine, industrial Ethernet and wireless technologies are all the rage. Virtually every new product now comes with an Ethernet port, and enough wireless attachments are available to make any control or instrumentation product a wireless device. It would seem we are heading for a wireless, Ethernet world.

But dont count out other technologies just yet. Established fieldbuses are making giant strides; one of the oldest networks of allModbusis gaining new life; and not everybody is sold on the newest technologies.

TALES FROM THE EDGEAs trends emerge more clearly, we usually can find a few early adopters to help define accompanying benefits. Ian Drazin is electrical and instrumentation supervisor at Potlach Corp., which produces coated printing papers, bleached paperboard and private-label tissue products in North Las Vegas, Nev. Drazin says Potlach went wireless four years ago in its warehouse and production area, primarily to control fork trucks, but he couldnt leave well enough alone.

I began redesigning our DH+ and Ethernet networks, connecting them to a field-mounted Allen-Bradley gateway, says Drazin. Once complete, I connected the company LAN to the gateway. Now, from my office, I can route communications through the gateway and gain access to my PLC processors. To make it better, I then coerced my IT department to install 802.11b wireless PCMCIA cards in our maintenance laptops. Armed with such a tool, I could connect to the PLC via my laptops wireless connection and walk up to the equipment I was working on and see input/outputs in real time.

Drazin enjoys many benefits from this system, including wireless Internet access. Many equipment manufacturers finally are making comprehensive product information available on their websites, he notes. Maintenance personnel save time if they have immediate access to product drawings, specifications, user manuals, set-up procedures, etc.

Joe Markham, control engineer at biopharmaceutical manufacturer Protein Design Labs, Brooklyn Park, Minn., uses industrial Ethernet in his process development group. We have a number of PLCs, operator interfaces and PCs connected via Ethernet, he reports. Ethernet is fast, especially compared to going via serial port out to a KF2 box, and onto DH+. Also, with Ethernet we can leverage the business infrastructure. We have our switches configured, so only selected engineering people can access the control system Ethernet LAN via the business LAN. This lets the engineers connect to the control system components from anywhere, while keeping the LANs isolated.

The downsides to wireless networks are security, dead spots, unexplained loss of connection and slower data transfer but wireless works surprisingly well. even in high RF industrial manufacturing environments.

Engineers with laptops especially benefit. Laptops all come with Ethernet these days, but none of them come with DH+, Profibus, or any other control LAN technology, he notes. While Drazin enjoys the benefits of wireless, he wont use it for control. The downsides to wireless networks are security, dead spots, unexplained loss of connection and slower data transfer, he laments. However, hell continue to use it for the purposes noted above. Personally, the benefits are so great that Im willing to put up with the negatives. I also want to mention that wireless technology works surprisingly well even in high RF industrial manufacturing environments.

But thats the limit for him, adds Drazin. I havent installed, nor do I plan to install, wireless instrumentation, he states. Believe me, I have thought about it. The current technology is just not there yet. I relate 802.11b/g to Windows 95. It works but it is unstable and quirky. Perhaps 802.11z will be the ticket.

Markham also has tried wireless. At a previous job, we used wireless data terminals extensively, he says. These were basically wireless VT100 terminals with a barcode scanner built in. They interfaced with a custom inventory control app. Very nice for the warehouse people. The only downside was the several thousand-dollar-per-terminal cost for units certified for use in flammable environments, and the fact that they had an average lifetime of about 12 months.

While Markham is willing to try wireless again, he has some reservations. I don't want anything that's just been introduced, he says. At that point, nobody knows all the interoperability tricks. The vendor's support people might not even have heard of it yet, firmware problems are notoriously difficult to track down, and promised software updates nearly always ship latesometimes years late.

A paper mill in Canada recently installed a process control system on a new paper machine. We wanted to use proven technology, says plant manager [[NAME???]], so we didnt want to use wireless or Internet technologies for control. His paper machine uses seven different networks, including Ethernet/IP, Foundation fieldbus, Profibus, DeviceNet, ControlNet, Bailey Ring and HART.

The integration of these networks seems to have gone off without a hitch. We invited the vendors of eight major systems representing five different countries to a customer acceptance test, he says. We used OPC to connect the PC-based systems and RS-485 to connect the PLC systems.

Traditional networks go together easily because everyone understands them. If youre considering installing a modern network, you may want to consider this: Who will maintain it?

I have a network with 58 workstations and four servers, reports [[NAME???]] a control engineer at a chemical manufacturer [[NAME??]] in N.J. The workstations are located in the various control rooms. Because of downsizing, Ive been waiting for corporate support for more than six months, since we identified some significant networking problems. Prior to this, I waited for almost a year for the technical support to identify the problems.

If you too rely on your IT department, you may run into the same situation. Our technical experts, whove spent most of their careers installing office networks, assume that an occasional re-boot to clear an error is acceptable, he says.

While keeping in mind that emerging technological edges can be sharp, maybe even dangerous, lets look at trends in industrial networks (See Figure 1 below).

FIGURE 1: HIERARCHY OF INDUSTRIAL CONTROL NETWORKS

UP FROM THE ASHESOne way to gauge the success of a technology is to note how many new products use it. While every product now comes with an Ethernet port, many also come with a Modbus port. Similar to the legendary phoenix, Modbus is rising from the ashes of the destruction that killed off many other networks that first saw light in the 1970s.

Why would a clunky network from the Dark Ages of control remain so popular? Bryan Moore, product manager at ABB, says Modbus probably will be around forever. It doesnt require special electronics, any PC or PLC can run it at the serial port, its very low cost, and it supports 256 stations, says Moore. Thats a lot, compared to a DeviceNet or Profibus network.

Yes, its slow. But that means it can cover long distances, Moore explains.

Yes, its rudimentary. But it has become a least common denominator, adds Moore, like the RS-232/serial ASCII connections of the past. You can always interface to it. Chances are, if you have any old control equipment or instrumentation in the plant, it probably has a Modbus interface.

WHAT ABOUT WIRELESS?Jumping from one of the oldest network technologies to the newest, lets look at wireless. Although some users are wary of wireless, it has taken center stage in the industrial networking theater. Sales are still at entry levels for a new technology (about $75 million in 2003), but market researchers predict good times ahead.

Venture Development says the market will grow about 35% annually, reaching $183 million in 2006. Frost & Sullivan projects that wireless sales will quadruple by 2006. A recent IDG. World Expo report goes even further, predicting that the wireless sensing technologies market (including sensors) will be greater than $10 billion by 2010.

Many big vendors are jumping on the wireless wagon. The HART Communication Foundation is adding wireless capability to its HART devices, and all the major control vendors are keeping an eye on what wireless is going to mean to process control and automation.

Gene Chen, product manager at Honeywell says that Honeywell is an executive sponsor of the three main bodies trying to define a wireless industrial standard. These include the Wireless Industrial Networking Alliance (WINA), ISA SP100, and ZigBee, a consortium of component-level OEMs. Gene Sierra, wireless marketing manager at Emerson Process Management, says that Emerson is working with HART and ISA.

Venture Development says its data agrees. It reports that mesh networks will grow from a miniscule $6 million in 2004 to $25 million in 2007, a growth rate of 60%.

Kagan sees tremendous opportunities for wireless sensors in process applications. Most process plants today take measurements at only about 10% of the possible points. But if the attachment and sensor costs were low enough, as mote technology promises, you could measure at many more points, giving you a much richer process model with which to work.

The biggest issue in wireless appears to be the lack of a universal standard. Three groups are working on it: WINA, ISA and ZigBee. Not having a single backbone slows down adoption, says Honeywells Chen. Several cases exist where customers spent resources to deploy wireless networks to support tablet PCs for operators, but found the network wouldnt support wireless sensors. Other customers had the opposite problem when they installed wireless sensors.

According to Venture Development analyst Jake Millete, ZigBee looks promising, but vendors are sticking to their proprietary methods. Many vendors feel ZigBee is an excellent solution for a variety of applications, notes Millete, but for industrial applications where a robust network is essential, some develop their own mesh networks. Well see many more ZigBee-based solutions in the industrial market as the standard matures.

This trend will have to solve another problem first. Power is a big issue. Wireless device-level network and sensors have yet to take off due to limitations of battery technology and lack of standardization, says Jonas Berge, marketing manager at Smar. Unlike wireless consumer devices such as mobile phones or PDAs, sensors cant have their batteries charged or changed every week. Conserving battery power is therefore very important. Because of the power problem, wireless sensors often transmit less often than wired sensors, and at slower speeds. As a result, wireless sensors are not suitable for control or functional safety, says Berge.

Slow response also happens when too much wireless traffic occurs nearby, so the sensor has to wait for the frequency to clear to transmit. No one wants to base a real-time control decision on inputs from a wireless sensor. For the immediate future, it appears that wireless will be limited to monitoring. (See this articles sidebar for a solution to both problems.

FIELDBUS FORGES AHEADThe October 2005 issue of CONTROL includes an account of a mammoth Foundation fieldbus project in SECCOs ethylene cracker complex in China. The DeltaV system from Emerson Process Management involves 10,000 fieldbus devices in 10 plants with 48,000 loops and 166,000 I/O tags. All PID control is performed in fieldbus instrumentation, and overall control and supervision comes from a central control room, where workstations run asset management, loop tuning and maintenance diagnostic software. The installation demonstrates the control capabilities of fieldbus, its ability to handle giant systems, and shows that it actually works.

Meanwhile, standards organizations are working hard to make fieldbus easier to use. Of greatest interest are Electronic Device Description Language (EDDL) extensions, says John Yingst, fieldbus systems product manager at Honeywell. This enhancement will provide a common means for device vendors to specify and interact with complex data such as valve signatures. EDDL has the support of the Fieldbus Foundation, HART, OPC and Profibus organizations, and EDDL is expected to make it easier for vendors and end users to implement all kinds of fieldbus instrumentation.

Fieldbus systems have been way ahead of the current trend toward remote diagnostics. On-line diagnostics available with Profibus include a status byte incorporated in the transmission of process variable data, explains Fabian Monino, senior applications engineer at Siemens Energy & Automation. This permits a control system to evaluate data and perform alarming if necessary.

Fieldbus also can be used in hazardous areas, but it is not considered a safety system, says Yingst. Significant changes would be required to adapt the FF protocol to the requirements of a safety standard. There is an ongoing effort to define a workable Safety Instrumented Systems (SIS) specification. Berge agrees. There are plenty of safety buses for the machinery/factory automation world, but nothing for process, he notes. FF-SIS is under development and already has TÜV concept approval.

In addition, Pilz has successfully integrated its PSS safety network with EtherNet/IP, ControlNet, Profibus and Interbus, and it developed a safe fieldbus technology of its own, called SafetyBus p. Lee Burk, training and consulting manager at Pilz, says the Ethernet protocol can be used, but Pilz believes a separate fieldbus should be implemented for communication of safety related signals.

"Supported by the Fieldbus Foundation, HART, OPC and Profibus organizations, EDDL is expected to make it easier to implement all kinds of fieldbus instrumentation."

One problem with fieldbus in hazardous areas is the power requirement. At the introduction stage of fieldbus technology, cabinet-mounted barriers and power supplies were the standard solution, explains Bernd Schuessler, business development manager at Pepperl+Fuchs. This solution barely supplied enough power for three or four instruments. Users complained, so standards organizations and manufacturers developed the FISCO (Fieldbus Intrinsically Safe Concept) and FNICO (Fieldbus Nonincendive Concept), which can power up to eight devices on a segment.

P+F also developed the High-Power Trunk concept, which allows up to 16 instruments in a segment. This allows end users to get the maximum number of devices on a segment, while also being able to achieve maximum cable lengths, says Schuessler.

Foundation fieldbus and Profibus-PA are the two most successful fieldbuses in process control, while Profibus-DP and DeviceNet appear to be the most successful in discrete automation.

We're seeing a very strong trend towards the use of Ethernet as a fieldbus, says Graham Harris, president, Beckhoff Automation. This is reflected in current I/O sales and in the emergence of technical organizations such as the EtherCat Technology Group. Over time, we'll see that the most successful Ethernet fieldbus technologies will be truly real-time, deterministic, offer a variety of wiring topologies, and push minimum cycle times below the millisecond mark. In addition, the cost of implementing these fieldbuses will continue to go down when standard cabling is used and off-the-shelf Ethernet cards continue to replace unnecessarily expensive fieldbus cards.

Sergei Furduy, a control engineer at Concept Systems (), a system integrator in Albany, Ore., sees the same trend unfolding. We still use DeviceNet in some applications, but more often we see DeviceNet being replaced by Ethernet, he says. One reason for this is that Ethernet interfaces typically cost less to install than DeviceNet.

Though he says DeviceNet still is used in applications requiring highly deterministic real-time control, the trend is toward localization of control tasks in small PLCs, such as ControLogix PLCs, which connect via Ethernet to existing networks.

Furduy adds that, There are fieldbuses that will continue to be used for factory networking. For example, we occasionally use Profibus, but this is when Siemens PLCs are being used. But it all winds up on Ethernet. No matter what control bus is being used, factory data base connectivity typically drives the need to provide connections via Ethernet, he concludes.

ETHERNET STILL GOING STRONG Ethernet is probably the most popular network in the world, thanks to its long life and use by all WinTel (Windows/Intel) systems. Just about every industrial network has an Ethernet version, including Foundation fieldbus (HSE), Profibus (Profinet) and our old friend, Modbus (Modbus TCP/IP). Various Ethernet hardware is used by big vendors such as Emerson, Rockwell and Omron. All the various protocols can run on the same Ethernet cable at the same time, and OPC Data eXchange software lets various Ethernet devices read the other protocols.

Without OPC, connecting various Ethernets is a problem, because there are so many. Its important that users understand the differences between standards-compliant networks and standards-based networks, says Doug McEldowney, Netlinx strategic marketing manager, Rockwell Automation. Standards-compliant networks, like Ethernet/IP, HSE, and Modbus TCP/IP use existing, unmodified networking components and networking standards to define their solution.

Berge puts it more bluntly: If the product specification just says Ethernet or TCP/IP without specifying the application protocol, you can be certain it is proprietary. Every vendor is jumping aboard the Ethernet train, and for good reason: it is dominating the industry.

A major factor pushing Ethernet lower in the factory is the increasing use of remote diagnostics and remote monitoring. As a recent Control Design web poll indicates, 47% of machine builders are incorporating web-based diagnostics.

At a minimum, products connected to Ethernet provide some level of diagnostics about the product and/or system via Web servers today, adds McEldowney. Also, the ability to leverage web services, in general, opens opportunities to connect dissimilar speaking devices within the enterprise. This area will continue to expand over time with more functionality being embedded deeper in the control systems.

OPC is working in that area, too. "We expect to release the new OPC Unified Architecture (OPC UA) spec by the end of the year," says Lee Neitzel, Emerson Process Managements senior technologist and editor of the new OPC UA spec. "The new OPC UA will permit OPC to be used across the Internet. By early next year, OPC applications will begin to communicate seamlessly using Internet communications wherever they are in the world. This will be a significant advance in automation system communications."

For users and OEMs, this will be another feature to add to the Ethernet steamroller. For competing networks, it may be another nail in their coffin.

With Wireless, Who Needs Networks?

HERE'S ONE SOLUTION to the power and speed problems with wireless proximity sensors that requires no batteries, operates as many times and as fast as needed, and suffers no delays or interference from other transmitters. Chris Jeffrey, business development area manager at ABB explains that several customers, including robotics, powertrain and stamping companies in the automobile industry asked his firm to help reduce their huge, ongoing costs associated with broken wires and worn/loose connections.

Jeffrey says sensor cables are one of the most frequent sources of failure in factory automation. "One automaker was spending about $40,000 per month just fixing wires on one machine," he says. "Wires and connections on robot arms, portable assembly pallets, platforms and anything else that moves will flex and break connections on a regular basis." It sounded like a battery-powered sensor was just the ticket.

Alas, replacing batteries, which never wear out on schedule, is just as much trouble as fixing wires. "If you have a machine with 50 battery-operated sensors, they all wear out at different times, depending on how often they are actuated," he says. Perpetually replacing batteries introduces a new maintenance nightmare. "Our wireless proximity switch design target was 10 years of maintenance-free operation, which ultimately means no batteries."

ABB developed a system that uses an electromagnetic field inside or around the machine (see Figure 2 below) to power all these wireless sensors. Because power is no longer a problem, the sensors (see photo) can operate continuously at high rates. Each sensor has a wireless transmitter that sends on/off signals to a base station. "ABB uses standard 2.4-GHz radio transceivers in its sensors, such as those used in Bluetooth, but employs a tailor-made real-time communication protocol.

FIGURE 2: ELECTROMAGNETICALLY ENCLOSEDWireless proximity switches have a ferrite cube, rectifier and voltage regulator which supply power regardless of the sensors orientation in the magnetic field.

BLUETOOTH is a general-purpose radio, originally developed for computer peripheral communication in offices. It is not usually considered for industrial real-time use in control systems. Likewise, Jeffrey says, ZigBee will be suitable only for data collection and non-time-critical devices, like in building automation.

"ABBs wireless technology WISA (Wireless Interface to Sensors and Actuators) is designed specifically for on-line sensor/actuator communication in factory automation control applications," adds Jeffrey. This means hundreds of nodes have to communicate in the 10 msec range. This requires a previously unheard-of level of timing and high reliability, especially in the presence of a wide variety of industrial disturbances.

Jeffrey says work is ongoing to add position encoders, other machine sensors and field I/O devices to the product list. He also says it may be possible in the near future to power actuators and even motors via the electromagnetic field. The implications of this technology are interesting, if not staggering. Jeffrey is talking about the possibility of a completely wireless machine; that is, no power wires, no I/O wiring, and no hardwired machine network. The only contact the machine would have to the outside world would be from its base station and PLC.

Extend the concept to hazardous areas, unit process controllers, skid-mounted systems, distillation columns, machine tools, and anything else that can be enclosed in an electromagnetic field, and it could spell the end to all the standard fieldbuses, device buses and I/O networks. This is definitely a development to watch.

Publish-Subscribe in Real Time

ANOTHER POTENTIAL network trend involves the newest real-time networking system for the WinTel platform: the OMG Data-Distribution Service (DDS). This is a publish-subscribe scheme that works with Windows operating systems. It hasnt exactly caught fire, but it shows promise in its ability to make WinTel systems more suitable for networking in an industrial environment.

Many real-time applications must model some of their communication patterns as a pure data-centric exchange where applications publish, supply or stream data, which is then available to any interested application, explains Gerardo Pardo-Castellote, Ph.D., chairman of the DDS Standards Committee and chief technology officer of Real-Time Innovations. These applications include industrial automation and distributed control. The lack of standards in this area forced application developers to use proprietary solutions or develop the infrastructure themselves. With the recent introduction of the OMG Data-Distribution Service for Real Time Systems, there are now COTS products that provide this infrastructure.

In a nutshell, this means the classic way of accessing data remotely in a standard WinTel system, using simple read and write instructions, doesnt work well in real time. An instantaneous response cant be guaranteed in an Ethernet LAN or WAN where computers enter and leave, and links have sporadic faults. The data-centric scheme in DDS, however, provides the performance, predictability and resource control required by embedded and real-time systems.

Kuka Controls recently announced the successful integration of RTIs version of DDS (NDDS) into its VxWin operating system. The combination allows Wind River VxWorks and Windows XP Embedded to run on the same host processor and share data with a publish-subscribe scheme. Operations are unaffected by Windows events, ensuring failsafe real-time operations.

RTI intends to market its DDS product into the industrial space. We will combine our NDDS with new tools for distributed system visualization, analysis and real-time debugging, says Stan Schneider, CEO of RTI. This platform will simplify design, ease development, and improve the quality and performance of real-time embedded systems in industrial automation applications.

Biweekly updates delivering feature articles, headlines with direct links to the top
news stories that are critical to staying up to date on the industry — company news,
product announcements, technical issues and more. Subscribe Today.